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2,153 Glossina palpalis palpalis caught in biconical traps from different biotopes in relation with human activities in the forest areas of Côte d'Ivoire were used to calculate the trypanosome infection rates. The results showed that there was no preferential biotope for Glossina infected by trypanosomes. The most widespread species of trypanosomes infecting Glossina p. palpalis is T. congolense (10.13%) followed by T. vivax (8.22%) and seldomly by T. brucei (0.70%). Female Glossina are infected with trypanosomes (21.27%) more than the male ones (13.56%). Regarding female Glossina, the physiological age concerned by the first infection of T. vivax, T. congolense and T. brucei reached respectively 5, 15 and 35 days. These different infection rates vary in relation to seasons.

A swine fever epizootic decimated the pig herds in villages within the Yamba focus of human trypanosomiasis. Ecological studies of Glossina palpalis palpalis populations were carried out in one of the villages for four years following the disappearance of the pigs, which had been the principal nutritive host of the Glossina in the area. One important behavioural modification occurred, namely the establishment of a small peridomestic tsetse population. The flies deserted the patches of residual forest to settle around the periphery of the village. This probably occurred in numerous other villages where the epizootic had destroyed the herds of pigs. The modified behaviour has increased the man-fly contact, but, on the other hand, facilitates vector control.

The biometric analysis of the male genitalia of Glossina palpalis palpalis and Glossina palpalis gambiensis about samples caught along four bits of road in Côte d'Ivoire permitted to determine the geographic limit between both subspecies. G. p. palpalis is everywhere in the Guinean area whereas G. p. gambiensis is found in the Sudanese one. In the wet savanna, both subspecies live together and mate to give out a reduced number of hybrids.